Combined variable resistor assembly provided with position indicator means

ABSTRACT

There is provided a combined variable resistor assembly provided with position indicator means for indicating positions of individual variable resistors by respective bright spots adapted to be moved by manipulating the associated variable resistors. This variable resistor assembly may find use mainly for electronic tuners, and with which the present states of the individual variable resistors for volume control, balance control, sound quality control and so forth can be known at a glance at the indicator means.

United States Patent [191 Nishioka et a1.

1 1 Nov. 11, 1975 COMBINED VARIABLE RESISTOR ASSEMBLY PROVIDED WITH POSITION INDICATOR MEANS Inventors: Matsuo Nishioka; Shunzo Oka, both of l-lirakata; Akitoshi Miyashita, Suita; Kazuo Oshima, Osaka, all of Japan Matsushita Electric Industrial Co., Ltd., Kadoma, Japan Filed: Dec. 26, 1973 Appl. No.: 427,735

Assignee:

Foreign Application Priority Data 338/174, 162, 128-134; 340/380, 381; 116/116, 114 M, 124 R, 124A,115, 124.1, 124.2, 124.4, 129 L, 129 M; 240/1 EL, 8.16

[56] References Cited UNITED STATES PATENTS 2,198,443 4/1940 Paul et a1. 116/129 L 2,437,355 3/1948 Greenslade. 338/196 X 3,118,422 1/1964 McNamara. 240/1 EL 3,588,780 6/1971 Takimoto 338/119 X 3,593,152 7/1971 Aoki 116/116 3,624,582 11/1971 lwusaki 338/196 X 3,641,471 2/1972 Labude et a1. 338/128 3,647,986 3/1972 Lace et a1, 340/380 X Primary E.\'aminerBruce A. Reynolds Attorney, Agent, or FirmStevens, Davis, Miller & Mosher [5 7 ABSTRACT There is provided a combined variable resistor assembly provided with position indicator means for indicating positions of individual variable resistors by respective bright spots adapted to be moved by manipulating the associated variable resistors. This variable resistor assembly may find use mainly for electronic tuners, and with which the present states of the individual variable resistors for volume control, balance control, sound quality control and so forth can be known at a glance at the indicator means.

9 Claims, 1 1 Drawing Figures L g f L J L 1 -r2 29 O 0 :L 3

o AMI r. o 61, o

.U.S. Patent Nov. 11,1975 Sheet1of6 3,919,681

U.S. Patent Nov. 11, 1975 Sheet2of6 3,919,681

ndE

U.S. Patent Nov.11, 1975 Sheet3of6 3,919,681

US. Patent N0v.11, 1975 Sheet4'of6 3,919,681

US. Patent Nov. 11,1975 Sheet50f6 3,919,681

'llllllmllm U.S. Patent N0V.11,1975 Sheet6of6 3,919,681

COMBINED VARIABLE RESISTOR ASSEMBLY PROVIDED'WITH POSITION INDICATOR MEANS This invention relates to a combined variable resistor poses are represented by the positions of respective bright spots which are displaced in accordance with the movement of the contacts of the corresponding variable resistors, whereby the present states of the individual variable resistors can be known by a glance at the indicator means.

According to the present invention, the position indicating bright spots are moved according to the variable resistance of the corresponding variable resistors, so

- that the present-states of various controls such as the volume control, balance control and sound quality control ,can be known at a glance, and thus it is possible to increase the commercial value of the combined variableresistor assembly as a set. Also, the assembly is simple .in construction and can be inexpensively provided. Thus, the present invention can offer great practical benefits.

The aforesaid and other objects, features and advantages of the present invention, will be apparent from thefollowing description taken in conjunction with the accompanying drawings, in which:

I FIG. 1 is a front view of an embodiment of the combined. variable resistor assembly provided with position indicator means according to the present invention;

FIG. 2 is a side view of the same'e'mbodiment;

FIG. 3 is a fragmentary perspective view, to an enlarged scale, showing the same in an exploded state and viewed from the back side thereof;

FIG. 4is a side view showing a rotatable variable resistor employed for the same embodiment;

FIG. 5 is a front view of another embodiment of the present invention;

FIG. 6 is a side view of the same;

FIG. 7 is a front view of a further embodiment of the present invention; I

FIG. 8 is a side view of the same;

FIG. 9 is a front view of a still further embodiment of the present invention;

FIG. 10 is a side view of the same; and

FIG. 11 is a sectional view, to an enlarged scale, showing the same embodiment.

An embodiment of the present invention will now be described with reference to FIGS. 1 to 4.

Referring to these FIGURES, and particularly to FIGS. 1 to 3, there is shown a panel casing 1 having a front wall and side walls. The front wall is formed with I a plurality of vertically extending parallel slots 2. An

H-shaped slide member 3 is slidably received in each slot 2, with its opposite side recesses engaged with the wall portions 5 adjacent the opposite edges of the slot 2 so that it is movable along the wall portions 5 as the guide. Numeral 6 (FIG. 3) designates a belt, which is secured at its one end to one edge portion ofthe associated slide member 3, and whose other end is securedly fitted in a groove formed in a cylindrical drum 7 so that it can be taken up on the periphery of the drum 7. The

drum 7 is accommodated in a hole or cavity 9 formed in the front wall of the casing 1 at a position below the lower end of the associated slot 2, and it is formed with a central see-through bore 10. The front wall of the casing 1 is also fo'rmedon its back side with a plurality of narrow grooves 11 each extending along the associated slot 2 and terminating in the associated cavity 9, the groove slidably receiving and guiding the corresponding edge portion of the associated belt 6 so as to prevent the buckling of the belt 6 and ensure smooth transmission of the rotation of the drum 7 to the associated slide member 3.

Extending through the bore 10 of each drum 7 is a rotatable shaft 13 of a rotatable variable resistor 12. Each rotatable variable resistor 12 is supported on the back side of the panel casing 1 by means of a bracket 14 secured by bolts 15 to the casing. Each drum 7 is secured by a clamp screw 16 to the shaft 13 penetrating the bore 10 so that it rotates in unison with the shaft 13.

Each rotatable variable resistor 12 has a well-known construction, as typically shown in FIG. 4, comprising a support plate 17 carrying the resistor proper and contact means (both resistor and contact means being not shown), a metal cover 18 tied at an open end thereof to the support plate, a brush holder (not shown) interposed between the support plate 17 and metal cover 18 and carrying brush means (not shown) electrically connected to the afore-mentioned resistor and contact means, the aforesaid shaft 13 which is integral with or rotatable in unison with the brush holder, and end terminals 19 and an intermediate terminal (not shown), these terminals being electrically connected to the resistor and contact means respectively and extending straight and in the same direction from the support plate 17.

Each rotatable variable resistor 12 is provided with a click detent mechanism. More particularly, the brush holder, which is rotatable in unison with the shaft 13, is provided arm 22 resilient member constituting a spring arem' 11 and having a ball or round head 21 at the free end, the ball or round head being adapted to be clicked into successive holes formed in a click plate 20. The

click detent mechanism is covered by a dust-proof case 23.

Numeral 24 (FIGS. 2 and 3) designates optical fibers each having one end portion received in and held in position in a hole formed in the associated slide member 3. The other end of the optical fibers 24 is held in position in the neiborhood of light source 26 (FIG. 1) mounted in the top portion of the front wall of the casing 1. In this example, two light sources 26 are mounted via respective holders 27 in the casing 1, and the other end of each optical fiber 24 is supported in the neiborhood of either one of these light sources. Each optical fiber 24 has a sufficient length to be able to follow the movement of the associated slide member 3.

Numeral 28 designates a push lock switch mounted on the bracket 14 secured to the casing 1. It may be operated to open or close the circuit of the light sources 26 or other circuits. Numeral 29 designates graduation marks provided on the front wall of the casing 1 and located in the vicinity of the respective slots 2. A click point of the afore-mentioned click action is adjusted to coincide with the graduation marks 29 when securing each drum 7 to the associated shaft 13 by the clamp screw 16. Numeral .30 designates notches formed in a ,3 top portion of the front wall of the casing 1 and terminating in the respective slots 2. They'are required for fitting the slide members 3 in engagement with the respective slots 2 formedin the casing 1.- The shaft 13 has a knurled portion 31 which is fitted in thedrurn .7. The knurling is provided to prevent the lost rotation of the shaft 13 after the fastening of the clamp screw16.

In operation, by rotating the shaft 13 of anyrotatable variable resistor 12, the associated brush holder also rotated in unison, causing the slidingmovement of the brush means secured to the brush holder over the resistor. Since the contact means is always in contact with part of the brush means, it is thus possible to take out a variable resistance between either one of the end terminals and the intermediate terminal. 1

Meanwhile, with the rotation of the shaft 13 the associated drum 7 is also rotated in unison, and this rotation is transmitted through the belt 6 to the slide member 3. In other words, the rotational motion of the shaft 13 is converted through the drum and belt 6 into a corresponding translational motion of the slide member 3, that is, the slide member 3 is moved in accordance with the rotation of the shaft 13. The movement of the slide member 3 means the movement of the free end of the associated optical fiber 24. Since the other end of the optical fiber 24 is held in the neiborhood of the light source 26, in the on state of the light'source 26 the movement of the free end of the optical fiber is observed as the movement of a bright spot. Since the movement of the bright spot andchange of the resistance of the variable resistor 12 are simultaneously caused by turning the shaft 13, the resistance taken out can be represented by the corresponding position of the bright spot.

. Also, with the rotation of the shaft'13, the spring arm 22 is rotated in unison, causing the ball or round head to successively fall into the click holes in the click plate 20,50 that successive click detent actions can be obtained. Here, it is also possible to adjust a mid point between two adjacent click points of the click action to coincide with the graduation mark.

FIGS. and 6 show another embodiment of the invention. In the FIGURES, numeral 101 designates a panel made of a metal plate and formed with a plurality of vertically elongate parallel openings or windows 102. Numeral 103 designates slidable vertical resistors corresponding in number to the number of the elongate openings 102. They extend parallel and are secured by means of screws 104 to the back side of the panel 101, each of them having a slide lever 105 penetrating, the associated elongate opening 102.

Each of the slidable variable resistors 103 has a wellknown construction, comprising a support plate 106 carrying the resistor proper and contact means (both resistor and contact means being'not shown), a metal cover 107 tied at an opening thereof to the support plate 106, a slidemember 108 extending between the support plate 106 and metal cover 107 and carrying brush means (not shown) slideable over the resistor and contact means, the aforesaid slide lever 105 secured to the slide member 108 and extending through a guide slot 109 formed in the metal cover 107, and terminals 110 and 111 electrically connected to the resistor and contact means respectively and taken out of the support plate 106. I

Rotatable shafts 112 corresponding in number to the number of the slidable variable resistors 103 are journaled in respective bearings 113 mounted in the panel 4 101 below the slidable range of the respectively associated slide levers 105. Each shaft 112 is provided with a lower pulley 114 secured to its portion extending on the front side of the panel 101. Numeral 115 designates anelongate click plate secured, by corking the shafts -forinstance, to a lower portion of the panel 101 on the frontside thereof. Each lower pulley 114 is provided on its side facing the click plate 115 with a resilient member 116 constituting a spring arm and having a ball or round head 117 at the free end, the ball or round head 117 being adapted to be successively clicked to the resiliency of the spring arm 116 into a plurality of click holes (not shown) formed in the click plate 115. Thus, each shaft l12 may be turned with a sense of click detent effect as the ball or round head 117 successively falls into the click holes in accompaniment of the rotation of the spring arm 116 in unison with the shaft 112. Each shaft 112 is provided with two stopper pins 118 extending from its end portion extending on the back side of the panel 101. These stopper pins 118 are adapted to engagewith a stopper protrusion 119 protruding from the panel 101, thus limiting the rotational angle or angular span of the shaft 112. Paired with the lower pulleys 114 are upper pulleys 120, which of course correspond in number to the number of the slidable variable resistors 103 and are mounted for rotation onrespective rivets 121 extending from the front side of the panel 101 above the slidable range of the respectively associated slide levers 105; Each slide lever 105 is tied to a rope 122, whichis passed round the associated upper and lower pulleys 'and'114 in pair and is connected at the opposite ends to a coil spring 125 to form a loop, the coil spring 125 serving to hold the rope 122 under a constant tension. The rope 122 is wound round the lower pulley 114 atleast one turnso that the rotation of the shaft 1 12 may be securely trans- ,mitted to the rope 122. The upper pulley 120 serves as an idler. Each slidelever 105 is thus moved with the rotation of the associated shaft 112 through the associated rope 122.

. Numeral 126 designates optical fibers each of which has one end secured to an end portion of the associated slide lever .105, penetrates the associated elongate opening 102 .formedin the panel 101 and hasthe other end held in position in the neiborhood of a light source 127. In this example, two light sources 127 are mounted via respective holders 128 in the panel 101, and the other end of each optical'fiber 126 is supported in the neiborhood of either one of these light sources. Each optical fiber 126 has a sufficient length to be able to follow the movement of the associated slide lever 105. The optical fibers 126 and slide levers 105 are arranged such that they will not interfere with the movement of the ropes 122.

Numeral 129 designates a push lock switch secured to panel 101. The push lock switch 129 is operated to open and close the circuit of the light sources and the other circuits. Numeral 130 designates attachment holes formed in the panel 101 for assembling it in a set using it. i

In operation, by turning anyshaft 112, its rotation is transmitted to the associated rope 122 through the pulcausing the sliding movement of the brush means secured to the slide member 108 over the resistor and contact means. in this way, it is possible to take out a variable resistance betweeneither one of end terminals 110 and the intermediate terminal 111.

Meanwhile, with the movement of the slide lever 105 the free end of the associated optical fiber 126 is.also moved in unison. Since the other end of the optical fiber 126 is held in the .nciborhood of the light source 127, with the light source 127 in the on state the move ment of the free end of the optical fiber is observed as the movement of a bright spot. ln other words, since the movement of the bright spot and change of the resistance of the variable resistor 103 are simultaneously caused by turning the shaft 112, the resistance taken out can be represented by the corresponding position of the bright spot.

Also, with the rotation of the shaft 112 the spring arm I 116 is rotated in unison, causing the ball or round head 117 to successively fall into the click holes formed in the click plate 115, thus providing the sense of the click detent effect.

It may be again worthwhile here to provide the panel 101 with graduation marks for the respective position indicators and adjust a click point of the click action to coincide with each graduation mark.

FIGS. 7 and 8 show a further embodiment of the invention. 1n the FIGURES, numeral 201 designates a panel made of a metal plate. It is formed with a plurality of vertically extending parallel slots 202; A slide member 203 is slidably received in each slot 202 of the panel 201. Numeral 204 designates rotatable variable resistors corresponding in number to the number of the slots 202, and each of which is mounted on the back side of a lower portion of the panel 201 with its rotatable shaft 205 extending to the front side of the panel.

Each rotatable variable resistor 204 has a wellknown construction, comprising a support plate 206 carrying the resistor proper and contact means (both resistor and contact means being not shown), a metal cover 207 tied at an open end thereof to the support plate 206, a brush holder (not shown) interposed between the support plate 206 and metal cover 207 and carrying brush means (not shown) electrically connected to the aforesaid resistor and contact means, the aforesaid shaft 205 which is integral with or rotatable in unison with the brush holder. and end terminals 208 and an intermediate terminal (not shown), these terminals being electrically connected to the resistor contact means and extending straight and in the same direction from the support plate 206.

corresponding in number to the number of the rotatable variable resistors and paired with the respective lower pulleys 209. The lower and upper pulleys 209 and 210 in each pair are located below and above the span of the each associated slide member 203. Each upper pulley 210 is mounted for rotation on a rivet 211 extending from the front side of the panel 201. Each slide member 203 is tied to a rope 212, which is passed round the associated upper and lower pulleys 210 and 209 and is connected at its opposite ends 213 and 214 to a coil spring 215 to form a loop, the coil spring 215 serving to hold the rope 212 under a constant tension. The rope 212 is wound round the lower pulley 209 at least one turn so thatthe rotation of the shaft 205 may 6 be securely transmitted to the rope 212. The upper pulley 210 serves as an idler. Each slide member 203 is thus moved with the rotation of the associated shaft 205 through the associated rope 212.

Numeral 216 designates optical fibers each of which has one end secured to the associated slide member 203 and the other end held in position in the neiborhood of a light source 217. Here, two light sources 217 are mounted via respective holders 218 in the panel 201, and the other end of each optical fiber 216 is supported in the neiborhood of either one of these lignt sourcesv Each optical fiber 216 has a sufficient length to be able to follow the movement of the associated slide member 203. The optical fibers 216 and slide members 203 are arranged such that they will not interfere with the movement of the ropes 212.

Numeral 219 designates a push lock switch secured to the panel 201. The push switch 219 is operated to open and close the circuit of the light sources 217 and other circuits. Numeral 220 designates attachment holes formed in the panel 201 for assembling it in a set using it.

In operation, by turning any shaft 205, its rotation is transmitted to the associated rope 212 through the pulleys 209 and 210, thus causing the movement of the rope 212 and hence the movement of the associated slide member 203. With the rotation of the shaft 205, the associated brush holder of the rotatable variable resistor 204 is also rotated in unison, causing the sliding movement of the brush means secured to the brush holder over the resistor. Since the contact means is always in contact with part of the brush means, it is thus possible to take out a variable resistance between either one of the end terminals and the intermediate terminal.

Meanwhile, with the movement of the slide member 203 caused through the rope 212 and pulleys 209 and 210 due to the rotation of the shaft 205, the free end of the associated optical fiber 216 is also moved in unison with the slide member 203. Since the other end of the optical fiber 216 is held in" the neiborhood of the light source 217, with the light source 217 in the on state the movement of the free end of the optical fiber is observed as the movement of the bright spot. Since the movement of the bright spot and change of the resistance of the variable resistor 204 are thus simultaneously caused by turning the shaft 205, the resistance taken out can be represented by the corresponding position of the bright spot.

Again here, it may be worthwhile to provide each rotatable variable resistor 204 with a click detent mechanism and the panel 210 with graduation marks for the respective position indicators and adjust a click point of the click action of each click detent mechanism to coincide with each graduation mark.

FIGS. 9 to 11 show a still further embodiment of the invention. In the FIGURES, numeral 301 designates a box-like metal casing, and numeral 302 an insulating plate tied to the casing 301 at a back side opening thereof. The front wall of the casing 301 is formed with a plurality of parallel slots 303 and also the same number of parallel slots 304 paired with the'respective slots 303. The insulating plate 302 carries resistors 305 (FIG. 11) corresponding in number to the number of the slots 303 and also contact means 306 (not shown) associated with the respective resistors. The resistors 305 and contact means 306 extend parallel and face the respective associated slots 303, and respectively asthe top wall of the metal casing 301 and a bracket 311 I provided within thecasing 301, and the brush 310 carried by it is in mesh with the helical groove. The slide members 309 and drive shafts 312 are disposed to face on the outer side of the casing 301 and reaching a position in front of the associated slot 304. Each drive shaft 312 has a bevel gear 314 secured to its lower end. In mesh with each bevel gear 314 is a bevel gear 316 secured to a rotatable shaft 315 journaled in a bearing 317 mounted in the front wall of the casing 301. Each rotatable shaft 315 is provided on its end portion extending on the outer side of the casing 301 with a knob 318. The axis of the'bevel gear 314 is at right angles to the axis of the associated bevel gear 316, so that the rotation of the shaft 315 is transmitted in a direction normal to its axis. Each shaft 315 penetrates the insulating plate 302 and has a stepped 319 219 of an increased di-- ameter at its end remote from the knob 318. The stepped portion 319 serves as a stopper with respect to the pulling of the shaft 315 and also as a lock means to co-operate with a push lock mechanism 320, which is provided on the insulating plate 302. The shaft 315 can be locked in its advanced position by the push lock mechanism. When the shaft 315 is locked, the gears 314 and 316 are no longer in mesh with each other, so that the rotation of the shaft 315 will be lost and will not be transmitted.

Numeral 321 designates optical fibers each of which has one end secured to the projection of the associated arm 313 extending on the outer side of the casing 301, is led through the associated slot 304 formed in the easing 301 and a notch (not shown) formed in the insulating plate and has the other end held in the neiborhood of a light source 322. The light source 322 is mounted via a holder 323 on a support 324, which is in turn secured by suitable means to the insulating plate 302. Each optical fiber 321 has a sufficient length to be able to follow the movement of the associated arm 313 and is arranged such that it will not interfere with the operation of the slide member 309 and drive shaft 312.

In operation, by turning any one of the shafts 315 its rotation is transmitted through the bevel gears 316 and 314 to the associated drive shaft 312 provided its stepped portion 319 is not coupled to the associated push lock mechanism 320, thus causing the rotation of the drive shaft 312 penetrating the associated slide member 309. Since the brush 310 secured to the slide member 309 is in mesh with the peripheral helical 8 7 Meanwhile, with the movement of the slide member 309 the free end of the associated optical fiber 321 is alsomoved in unison. Since the other end of the optical fiber 321 is held inthe neiborhood of thelight-source I 322, with the light source 322 in the on state the movement of the free end of the optical fiber 321 can be observed as the movement of a bright spot. i

Here, it may be worthwhile to provide the front wall of the casing with graduations for reading the individual bright spots of the optical fibers 321.

While in the instant embodiment the metal casing 301 is formed with the slots 303 and 304,it'is possible to replace each pair of slots 303 and 304 with a single slot.

We claim: 7

1. A combined variable resistor assembly provided with position indicator means, comprising a panel casing formed with a plurality of parallel slots,'rotatable variable resistors corresponding in number to the number of said slots and mounted on said panel casing, slide members slidably engaged in said respective slots, drums each secured to an operable shaft of the associated one of said variable resistors, belts each having one end secured to the associated one of said drums and the other end secured to the associated one of said slide members, a light source, and optical'fibers each having one end held in the neiborhood of said light source and the other end connected to each said slide members. 1

2. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein each said belt has an edge portion sliclablyreceived in a groove formed in said panel casing near and along each said slot.

3. A combined variable. resistor assemblyprovided with position indicator means according to claim 1, wherein said panel casing isformed with openings having a size greater than the size of saidslide members and communicating with said respective slots.

4. A combined variable resistor assembly provided with position indicator means according to claim 1,

wherein each said slide member has a channel-shaped portion in slidable engagement with a wall portion of said panel casing adjacent each said slot.

5. A combined variable resistorassembly provided with position indicator means according to claim 1, wherein each said variable resistor ienludes a brush holder mounted rotatably on said operable shaft, said brush holder being provided with a resilient member serving as a spring arm and having at the free end thereof a ball or round head, and a stationary click plate formed with one or more click holes, said ball or round head being adapted to be clicked into said click hole or holes.

6. A combined variable resistor assembly provided with position indicator means according to claim 5, wherein each said variable resistor further includes a cover covering said resilient member having a ball or round head and said stationary click plate.

7. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein the operable shaft of each said variable resistor has a knurled portion, the associated drum being fitted on said knurled portion and secured by a clamp screw to said knurled portion.

. wherein all the terminals of each said variable resistor 3,919,681 9 I 10 v extend and the F- panel casing through a shaft aligned to said operable 9. A combined variable resistor assemblyprov ded with position indicator means according to claim 1, Shafts of sum vanabl? which further'comprises a switch mounted on said 

1. A combined variable resistor assembly provided with position indicator means, comprising a panel casing formed with a plurality of parallel slots, rotatable variable resistors corresponding in number to the number of said slots and mounted on said panel casing, slide members slidably engaged in said respective slots, drums each secured to an operable shaft of the associated one of said variable resistors, belts each having one end secured to the associated one of said drums and the other end secured to the associated one of said slide members, a light source, and optical fibers each having one end held in the neiborhood of said light source and the other end connected to each said slide members.
 2. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein each said belt has an edge portion slidably received in a groove formed in said panel casing near and along each said slot.
 3. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein said panel casing is formed with openings having a size greater than the size of said slide members and communicating with said respective slots.
 4. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein each said slide member has a channel-shaped portion in slidable engagement with a wall portion of said panel casing adjacent each said slot.
 5. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein each said variable resistor icnludes a brush holder mounted rotatably on said operable shaft, said brush holder being provided with a resilient member serving as a spring arm and having at the free end thereof a ball or round head, and a stationary click plate formed with one or more click holes, said ball or round head being adapted to be clicked into said click hole or holes.
 6. A combined variable resistor assembly provided with position indicator means according to claim 5, wherein each said variable resistor further includes a cover covering said resilient member having a ball or round head and said stationary click plate.
 7. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein the operable shaft of each said variable resistor has a knurled portion, the associated drum being fitted on said knurled portion and secured by a clamp screw to said knurled portion.
 8. A combined variable resistor assembly provided with position indicator means according to claim 1, wherein all the terminals of each said variable resistor extend straight and in the same direction.
 9. A combined variable resistor assembly provided with position indicator means according to claim 1, which further comprises a switch mounted on said panel casing through a shaft aligned to said operable shafts of said variable resistors. 